Who'll win the gold medal for partying? Olympians let their hair down in London

British gold medal-winning cyclist Bradley Wiggins is seen on stage at a concert in Hyde Park, left, enjoying a beer while watching Olympic action in the Velodrome, center, and meeting Stone Roses singer Ian Brown at a secret VIP gig by the band in London, right.

By Alastair Jamieson, NBC News

LONDON - After four years of intense training and personal sacrifice, athletes are letting their hair down and joining London’s city-wide Olympic party.

With many events now over, and with Sunday's closing ceremony looming, Olympians are becoming a more frequent sight on the streets – and in the bars – of Britain’s capital.

Many are turning up at venues to support their team-mates in the remaining competition -- and sign autographs for lucky spectators.

“It is nice for us now to be able to relax and watch some of the Games,” said Czech cyclist Denis Spicka, who was surrounded by friends and female fans at Czech House – one of dozens of temporary national ‘party houses’ set up around London by tourism promoters and sponsors.

Have you ever wondered what Olympic athletes do after the competition and medals? TODAY special correspondent Ryan Seacrest heads out into London to investigate, going to Ryan Lochte's birthday bash and getting the scoop on how Missy Franklin plans to commemorate her medals.

Spicka was one of hundreds of party-goers enjoying Czech beer while watching giant screens showing his country take on France at women’s basketball on Tuesday night – only hours after he had finished his own race in the Olympic Velodrome.

“The girls here are very nice,” he grinned.

Alastair Jamieson/NBC News

Officials from Britain's Olympic team enjoy a late-night take-out in east London's Mile End.

Across town, U.S. swimmer Ryan Lochte was enjoying a birthday party at a Planet Hollywood theme restaurant near Leicester Square. The 28-year-old enjoyed chicken fingers, nachos, Champagne and birthday cake, according to E!, before heading to Mahiki, a nightclub popular with Prince Harry.

It was not the gold medal winner’s first night of partying: He joined a throng of fellow swimmers including South African Jean Basson and Lebanese Katya Bachrouche at club Chinawhite on Sunday night.

Chad le Clos, the South African who beat Michael Phelps in the 200m butterfly last week, also dropped into the club, dancing with his team and some Australian swimmers. "It was pretty cool,” he told the Daily Telegraph. “Everyone was there, the Americans and the French team. Pretty much the whole of the VIP area was crawling with swimmers. We all enjoyed ourselves."

Others have been touring London’s sights or relaxing in and around the Olympic Park. Cook Islands swimming coach Romani Katoa was enjoying a few beers with fellow spectators at the track and field events on Sunday night, while Hungarian hammer-thrower Krisztian Pars was showing off his gold medal on the top floor of a double-decker bus.

In the Westfield shopping mall that leads to the Olympic Park, athletes from around the world have been signing autographs for fans or partying in the top-level casino.

Indeed, spotting athletes has now become a London tourist activity in its own right: Olympians from Rwanda were pictured waiting for a bus on Monday, officials from Team Great Britain were seen ordering a late-night take-out in a kebab house in east London’s Mile End and Tour de France winner Bradley Wiggins posted a picture of himself on Instagram “getting wasted” near St. Paul’s Cathedral after winning his cycling gold medal for Britain.

Wiggins and fellow British gold medalist Jessica Ennis were among the athletes who attended a VIP Stone Roses concert on Monday. The duo were reportedly introduced at the gig as "king" and "queen" of England.

At the Austria House near the Tower of London, where party-goers can enjoy pilsner and sauerkraut while watching live Olympic action, Austrian gymnast Fabian Leimlehner was among those signing autographs.

Jim Seida / NBC News

Julia Sailer from Innsbruck, Austria, pours two-liter beers as fast as she can sell them at Austria's national hospitality house in the Tower Hill area of London on Tuesday.

'So much debauchery'Speculation is now turning to life inside the Olympic Village – the super-private athletes-only area notorious for evolving into a party zone as the Games come to an end. In a now-notorious ESPN feature last month, Lochte predicted that “70 to 75 percent of Olympians” would be having sex with other competitors, adding: “Hey, sometimes you gotta do what you gotta do."

About 150,000 condoms have been handed out by organizers in the wake of of stories about goings-on at the Sydney 2000 games where, according to U.S. target shooter Josh Lakatos, competitors turned an empty room into a venue for round-the-clock casual sex, assisted by an Oakley duffel bag overflowing with condoms procured from the village's medical clinic. “I've never witnessed so much debauchery in my entire life," he told ESPN.

Traveling around traffic-plagued London can be a hassle at the best of times -- never mind during an event such as the Olympic Games. NBCNews.com put the city to the test in a race to the Olympic Park.

So are the beds of London’s Olympic village really shaking? “We are all sharing rooms, so it is difficult,” said Czech runner Josef Prorok at the Czech House party. “Our apartment is above the laundry area and some of my friends have discovered there are some empty places, so…”

In practice, he said, athletes prefer to head into the city to party. “There is no alcohol in the Village bar so it is boring there. Here there is a screen and there are people having fun, and girls,” he said.

His comments were echoed by former British Olympic swimmer Sharron Davies, who told The Mirror; “Any partying is done away from the Village out of respect for athletes who are still competing. To be honest you spend all your time training and eating healthily – and it only takes a glass of wine and you are hammered.”

All the better for Londoners, who are are cruising the national party houses in the hope of getting to meet athletes.

"Which is the best one?" asked Nick Watterson, from north London, who was drinking at the Czech House with friends after watching Olympic soccer at Wembley Stadium. "Brazil House sounds good. It's a great atmosphere in the city at the moment, a real party going on."